Philip Stewart

..The predictability of an antibiotic tolerance response is essential to developing, testing, and employing antimicrobial strategies...

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..Disabling biofilm resistance may enhance the ability of existing antibiotics to clear infections involving biofilms that are refractory to current treatments...

..The purpose of this study was to compare the efficacy, in terms of bacterial biofilm penetration and killing, of alkaline hypochlorite (pH 11) and chlorosulfamate (pH 5.5) formulations...

..In biofilms, resistance seems to depend on multicellular strategies. We summarise the features of biofilm infections, review emerging mechanisms of resistance, and discuss potential therapies...

..Catalase protects aggregated bacteria by preventing full penetration of hydrogen peroxide into the biofilm...

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..8-log enhancement of killing resulted. The enhancement of antibiotic killing by oxygen was not due simply to physical disturbances caused by sparging the gas because similar delivery of gaseous hydrogen caused no enhancement whatsoever...

..This result demonstrates that transport limitation can impact antimicrobial performance against biofilms not only of oxidizing biocides but also of nonoxidizing agents...

..The dependence of diffusion on antimicrobial and environmental challenges suggests the polymer molecular dynamics measured by NMR are a sensitive indicator of biofilm function...

..The model was also able to predict biofilm sloughing resulting solely from this detachment mechanism. These results support the conjecture that nutrient starvation is an environmental cue for the release of microbes from a biofilm...

..The LCMM/qRT-PCR technique can be used to resolve and quantify this RNA variability at high spatial resolution...

..This suggests chitosan disrupts cell membranes as microbes settle on the surface. Chitosan offers a flexible, biocompatible platform for designing coatings to protect surfaces from infection...

..Bacterial biofilm prevalence in specimens from chronic wounds relative to acute wounds observed in this study provides evidence that biofilms may be abundant in chronic wounds...

..6 x 10(-6) cm(2) s(-1), or 32% of the value in water. This study provides direct, visual confirmation that solutes the size of many antibiotics and biocides can diffuse rapidly into biofilms...

..The CAM staining technique has the potential to provide information about the rate of antimicrobial penetration, the presence of tolerant subpopulations, and the extent of biomass removal effected by a treatment...

..The diffusion coefficient of daptomycin in the biofilm was 28% of its value in pure water. Daptomycin activity against staphylococci embedded in biofilms is unlikely to be limited by penetration of the antibiotic into the biofilm...

..Understanding biofilm rheology and how it is affected by chemical treatment could lead to improvements in biofilm control...

..The data demonstrate the ability of magnetic resonance microscopy to study spatially resolved processes in bacterial biofilms, thus providing a basis for future studies of spatially resolved metabolism and in vivo clinical detection...

..The variety of activity states represented in a biofilm may contribute to the special ecology and tolerance to antimicrobial agents of biofilms...

..The entire procedure takes 13 h of active time that is distributed over 5 d...

..aureus planktonic cells and biofilms inhibit scratch closure. Furthermore, S. aureus biofilms significantly reduced HK viability and significantly increased HK apoptosis compared with planktonic S. aureus...

..These results show that while mature P. aeruginosa biofilms contain active, growing cells, they can also harbor large numbers of cells that are inactive and not growing...

..Because the bacteria nevertheless survived antibiotic treatment, some protective mechanism other than inadequate penetration must have been at work in the biofilm...

..In many cases, bacteria have been shown to gain a fitness advantage when residing in a mixed-species versus single-..

..These results underscore the distinction between biofilm removal and killing and reinforce the critical role of biocide reactivity in determining the rate of biofilm penetration...

..This work provides a more detailed quantitative experimental observation of biofilm behaviour than has been described previously...

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..This modelling study provides motivation for further investigation of the hypothetical persister cell state as an explanation for biofilm resistance to antimicrobial agents...

..The results support the important contributions of nutrient limitation and slow growth to the antibiotic tolerance of microorganisms in biofilms...

..Local oxygen limitation and the presence of nitrate may contribute to the reduced susceptibilities of P. aeruginosa biofilms causing infections in vivo...

..Penetration was demonstrated by a simple diffusion cell bioassay and by transmission electron microscopic observation of antibiotic-affected cells at the distal edge of the biofilm...

..This study demonstrates the feasibility and limits of implementing biofilm-control strategies based on attacking the EPS...

..Arginine or nitrate also enhanced the killing by these antibiotics in mature biofilms, reducing viable cell counts by a factor of 10 to 100 beyond that achieved by antibiotics alone...

..These treatments resulted in killing (2.1-log reduction) and removal (4.0-log reduction) of viable cells at the anode and cathode, respectively, within a few minutes...

..Using these assays, agents can be ranked by their ability to remove or kill biofilm...

..Each of the mechanisms could be a plausible avenue of biofilm protection...

..In these inactive regions, bacteria are less susceptible to killing by antibiotics...

..aureus biofilm. These results demonstrate that multifunctional nanoplatforms based on protein cage architectures have significant potential as tools for both diagnosis and targeted treatment of recalcitrant bacterial infections...

..Since this is the "standard 1 mm" size capillary used in confocal microscopy laboratory bioreactors to investigate biofilm properties, it is important to understand how these enhanced flows impact bioreactor transport...

..The dynamics of biofilm decay during starvation were distinct for each detachment mechanism. These results show that detachment is a critical determinant of biofilm structure and of the dynamics of biofilm accumulation and loss...

..These results show that oxygen limitation and low metabolic activity in the interior of the biofilm, not poor antibiotic penetration, are correlated with antibiotic tolerance of this P. aeruginosa biofilm system...

..Our results indicate that biofilms themselves are not simply a diffusion barrier to these antibiotics, but rather that bacteria within these microbial communities employ distinct mechanisms to resist the action of antimicrobial agents...

..This observation makes sense when the different oxidative reactivities of chlorine, silver, and tobramycin are considered...

..These results suggest that biological treatment may be valuable in reducing membrane fouling while reducing the amount of disinfectants used in pretreatment...

..As these studies continue to refine our understanding of these mechanisms, an emerging challenge is to identify if and when the local environment can affect signaling...

..This project will afford a rich interdisciplinary training experience for the three participating graduate students. ..

..Furthermore, the results of this research may impact the treatment of other biofilm-related diseases, such as osteomyelitis, endocarditis, prostatitis, otitis media, and sinusitis. ..

..Futhermore, the results of this research may impact the treatment of other biofilm-related diseases, such as osteomyelitis, endocarditis, prostatitis, otitis media, and sinusitis. ..